Winding head

ABSTRACT

Device for producing a coil winding (33) from winding wire on a winding carrier (32) with a winding head (10) which has a wire guiding means (16) and is movable relative to the winding carrier (32) in which a wire connecting means (17) and a wire severing means (18) are provided in addition to the wire guiding means (16) as further integral parts of the winding head (10).

BACKGROUND OF THE INVENTION

The present invention relates to a device for producing a coil windingfrom winding wire on a winding carrier with a winding head which has awire guiding means and is movable relative to the winding carrier. Theinvention also relates to a method of producing an electricallyconductive connection which can be carried out using this device.

Devices of the aforementioned type can be used in the production of coilarrangements in which a wire conductor is wound round the windingcarrier to form a coil winding by means of a winding head and wire endsof the winding wire are connected to attachment surfaces of the windingcarrier or the adjacent components. To produce the connection betweenthe wire ends and the attachment surfaces, further means, namely aconnecting means and a wire severing means are required in addition tothe winding head. During the production of such a coil arrangement, itis possible to proceed such that a wire end is initially connected to anattachment surface by means of the connecting means, the actual coilwinding is then formed round the winding carrier by means of the windinghead and the travelling wire end of the winding wire is finallyconnected to a further attachment surface by the connecting means and issevered by the wire severing means. An arrangement of this type forcarrying out the method outlined hereinbefore described is described inPCT-Application PCT/DE92/00928 belonging to the applicant.

The plurality of means participating in the production of such a coilarrangement results in a complex construction with the known device,correspondingly high production times resulting, in particular, from thepaths to be covered by the winding head between the individual, locallyfixedly installed production stations (connecting station, severingstation).

The object of the present invention is to provide a generic device and amethod which allow a construction which is as compact as possible and areduction of the production times.

SUMMARY OF THE INVENTION

In the device according to the invention, the wire guiding means, theconnecting means and the wire severing means are integral means of thewinding head. A device of this type in effect provides a highlyintegrated winding head which, in addition to the actual wire guidingfunction, during the winding of a wire conductor onto a winding carrier,simultaneously performs the functions of connecting the wire ends to thewinding carrier or another separate attachment surface carrier and thesubsequent wire severing function. Owing to the combination in aconstructional unit, the entire device forms a compact arrangement sothe connection of the wire conductor to the attachment surface and thesevering of the wire conductor can take place in one and the samerelative position with respect to the attachment surface of theattachment surface carrier. Intermediate paths which are produced sincethe wire guiding means has to be guided from a connecting means to asevering means in devices according to the prior art are thereforeunnecessary when producing the connection.

Although the device according to the invention, as mentioned above, isparticularly suitable for the production of coil arrangements, that isfor carrying out a winding process and for producing connections, thedevice according to the invention can similarly be used to advantagequite generally wherever connections are to be produced at specificpoints between a wire conductor and an attachment surface and the wireconductor (by the winding/connecting device according to the invention,described herein as "winding head") is to be guided in the intermediateregion over a predetermined path of movement from one connecting pointto another connecting point. It is not necessary to perform a windingprocess in each case but a substantially meandering course in a plane orany other desired wire course between two connecting points can beproduced with appropriate axial control of the winding/connectingdevice.

In a preferred embodiment of the device according to the invention, thewire guiding means, the connecting means and the wire severing means arecombined in a tool head, the actuating or adjusting members required forthe individual means being arranged outside the tool head. Thisconstruction represents miniaturization which allows the deviceaccording to the invention also to be used with the smallest attachmentsurfaces such as the standard attachment surfaces of a chip measuringonly 100 micrometres×100 micrometres.

The wire guiding means is preferably provided with a wire deflectingmeans which allows a wire conductor supplied substantially parallel tothe connecting means to be deflected in order to save space transverselyto the adjustment axis of the connecting means so the wire conductorcomes to rest between the connecting means and the attachment surfacewhen producing the connection.

It is mentioned at this point that the connecting means is notrestricted to a specific type but rather can be selected at random fromthe number of connecting means available such as a thermode, athermosonic connecting means, a laser welding means, etc. or even acombination thereof.

When using a laser welding means, a means of the type described in DE-OS42 00 492 in which the laser power emitted by a laser source is conveyedby means of a glassfibre conductor directly to the connecting point hasproven particularly advantageous. Use of such a laser welding meanstogether with the device according to the invention affords theparticular advantage that the winding head does not have to be loaded bythe apparatus forming the laser source which can be arrangedstationarily remotely from the winding head. The glassfibre conductorcan then be integrated into the winding head as a connecting means. Thisallows a powerful laser welding means to be used in the device accordingto the invention without disadvantageously increasing its size by theabove-mentioned means.

It is also possible to combine the wire guiding means, the connectingmeans and the wire severing means overall or in part to form afunctional unit. For example, the wire guiding means can be combinedwith the connecting means in that, for example in the case of athermosonic bonding head as connecting means, the wire is suppliedthrough a capillary in the bonding head. It is also possible, ifnecessary, additionally to integrate the severing means in a functionalunit composed of wire guiding means, connecting means and wire severingmeans. An example of this would be a thermosonic bonding head which isprovided with a wire guiding capillary and also has a severing edgeformed in the wire contact region. A maximum of integration can beachieved in this way.

The wire, deflecting means is preferably formed by an aspirator actingtransversely to the adjustment axis of the wire guiding means. In thisadvantageous design of the wire deflecting means, the production thereofmerely requires a vacuum connection in the region of the connectingmeans which causes the wire conductor supplied substantially parallel tothe adjustment axis of the connecting means by the wire guiding means tobe deflected transversely to the adjustment axis of the connecting meansowing to the suction, so the connecting means can act upon the wireconductor, for example by thermal or pressure loading in the case of athermode.

A further possibility involves providing a gripper means pivotaltransversely to the adjustment axis of the connecting means for the wiredeflecting means.

In one possible embodiment of a wire deflecting means which is similarin principle but is preferred with respect to the compactnessachievable, the wire guiding means itself is designed to pivottransversely to the adjustment axis of the connecting means in orderthen to produce, in co-operation with the attachment surface of theattachment surface carrier which the wire conductor strikes, such adeflection of the wire conductor that the wire conductor comes to restbetween the connecting means and the attachment surface.

It has proven particularly advantageous if the device according to theinvention is constructed in such a way that the actuating or adjustingmembers allocated to the individual means are arranged in a tool headcarrier which can be coupled to the tool head. This allows a simpleexchange of tool head to be carried out if necessary to enablecombinations of tool head means to be adapted to one another in aparticular manner. For example, it may also prove advantageous,depending on the combination of materials of wire conductor andattachment surface, to use a connecting means of a specific type. Thus,the thermal compression method has proven advantageous, for example, fora connection on an attachment surface of a captone film and thethermosonic method with a chip attachment surface, and a combination ofthese methods is also conceivable. However, one and the same actuatingor adjusting member can invariably be used independently of the choiceof connecting means. In addition to simple and rapid tool head exchange,this has a desirable effect on the tool production costs.

The actuating or adjusting members can be designed in various ways. Forexample, they can be designed as compressed air actuating members suchas piston/cylinder units or as solenoid-type actuating members.

Furthermore, it is advantageous to provide a further wire guiding meansin addition to the above-described wire guiding means. This allows anadditional material such as gold or a gold alloy to be supplied asbonding wire, if necessary, for example if the materials of wireconductor and attachment surface cannot form a compatible joint, toguarantee a reliable, electrically conductive connection between thewire conductor and the attachment surface consisting, for example, of analuminium surface.

This further wire guiding means can be integrated into the connectingmeans.

A further advantageous method of producing or increasing thecompatibility of the connection between the wire conductor material andthe attachment surface material involves providing a protective gassupply means in the region of the connecting means.

According to a further variation, a vacuum means is provided in theregion of the connecting means, for example in that the entire tool headis surrounded by a vacuum bell.

The protective gas supply means can also be allocated a coating meanswhich allows the application of a protective layer to the connectingpoint, for example the application of a passivating layer as corrosionprotection, preferably during the loading of the connecting point withprotective gas.

To monitor and/or control the device according to the invention, thedevice can be provided, in a particular embodiment, with a camera, inparticular a CCD camera equipped with CCD (charge coupled device) imagesensors, which can be arranged on the tool head itself or also on thetool head carrier. The camera can also be integrated into the tool heador the tool head carrier depending on method of mounting.

The method according to the invention permitted by the use of the deviceaccording to the invention is also disclosed.

According to the invention, the device is used to connect a bondablewire conductor directly to the unbumped attachment surfaces of anelectronic component such as a chip. The wire is connected, for example,directly to the aluminium pads without bumps previously having beenapplied thereto. This results in a considerable simplification in theelectrical attachment of chips or in components which are comparablewith regard to the method of attachment.

It has proven advantageous if a bondable winding wire, preferably acopper bonding wire is used as wire conductor. This allows the deviceaccording to the invention firstly to be used for the winding of coilsand a direct connection to an unbumped attachment surface then to beproduced with one and the same wire.

It has proven particularly advantageous if the connection between thewire and attachment surface is made in a protective gas atmosphere orunder vacuum in order to increase the quality of the connection.

Preferred embodiments of the device according to the invention will bedescribed hereinafter with reference to the drawings with an explanationof the method according to the invention by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the device according to the invention in a first embodimentwith a tool head coupled to a tool head carrier.

FIG. 2 shows the device in an enlarged partial view after the winding ofa coil and the connection of winding wire ends to attachment surfaces ofa coil carrier.

FIGS. 3A to 3C show the tool head carrier in various configurations,succeeding one another in time, for forming a wire conductor connection.

FIG. 4 is a schematic illustration of the tool head in a first variationof the tool head shown in FIG. 1.

FIG. 5 is a schematic illustration of the tool head in a furthervariation of the tool head illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows, in a first embodiment, a winding/connecting device 10 witha tool head carrier 11 and a tool head 12. The tool head 12 isdetachably connected via a connecting element designed as a connectingsleeve 13 here to the tool head carrier 11. For the detachableconnection the connecting sleeve 13 has, in its end region facing thetool head carrier 11, an internal thread 14 which co-operates with anexternal thread of the tool head carrier 11 not shown in detail.

A camera, such as a CCD camera 9, can be arranged on the tool headcarrier 11, as shown in FIG. 1, or on the tool head 12 for monitoringoperation of the device 10.

The tool head 12 has a tool receiver 15 with tool means received andguided therein, namely a wire guiding means 16, a connecting means 17, awire severing means 18 and a wire deflecting means 19.

To permit an adjustment movement of the wire guiding means 16, theconnecting means 17 and the wire severing means 18 in the direction ofan adjustment axis 20, the aforementioned means are provided, at theirupper end in FIG. 1, with pneumatic piston/cylinder units 21, 22, 23provided as adjusting members. Damping means 25 can be provided betweenpiston rods 24 of the piston/cylinder units 21, 22, 23 and the ends ofthe means 16, 17, 18, as shown by way of example for the wire severingmeans 18.

In this case, the means 16, 17, 18 are coupled not directly to thepiston/cylinder units 21, 22, 23 but via the damping means 25.

The function of the winding/connecting device 10 is described in detailhereinafter.

FIG. 1 shows the winding/connecting device 10 in a winding configurationin which the wire guiding means 16 is located in a position advancedfrom the tool receiver 15. A winding wire 26 or generally a wire withwhich, for example, a wire connection is to be produced between twoattachment surfaces is guided through the wire guiding means 16 oftubular design. In this configuration, the winding/connecting device 10can be used in the conventional manner as a winding head which ismovable round one or more axes in space or generally as a wire guidinghead.

In order to connect the wire 26 to an attachment surface not shown indetail in FIG. 1 following a winding process or to a free wire end 27fixed in a different manner using the winding/connecting device 10 shownin FIG. 1, the tool head 12 is initially moved in the direction of thearrow 28 and the wire guiding means 16 driven into the tool head 12 byactuation of the piston/cylinder unit 21. The wire 26 is thus placed onthe underside of the tool head so the connecting means 17 can be drivenout of the tool head 12 until it rests on the attachment surface withinterposition of the wire 26. Depending on the distance between the toolhead 12 and the attachment surface, the winding/connecting device 10 canbe advanced overall in the direction of the adjustment axis 20.

Depending on the type of connecting means 17, the connecting meansoperates, for example, with thermal compression or ultrasonic exitationwith or without simultaneous heating of the attachment surface, the wire26 being connected to the attachment surface. After the connection hasbeen made, the severing means 18, which has the form of a severing bladein the embodiment shown in FIG. 1, is driven out in order to sever thewire 26 close to the connecting point.

This configuration of the winding/connecting device 10 is shown in FIG.2. The wire guiding means 16 is located in the retracted position andthe connecting means 17 and the wire severing means 18 in the advancedposition.

A vacuum bell 8 is also shown surrounding the tool head 12. The vacuumbell 8 acts as a vacuum means for producing a vacuum in the connectingregion as described in more detail below.

The configuration of the winding/connecting device 10 will be describedhereinafter with reference to FIGS. 3A to 3C, when producing a wireconnection, for example for fixing the wire end on an attachment surfacebefore carrying out a subsequent winding process or for a wireconnection between attachment surfaces. In FIG. 3A, in contrast to theillustration in FIG. 1, the wire guiding means 16, the connecting means17 and the wire severing means 18 are initially located in a completelyretracted position and clear a duct 30 extending transversely to theadjustment axis 20. The wire conductor, 26 supplied through the wireguiding means 16 is brought by the wire deflecting means 19 designed asan aspirator here with its free wire end in a position transversely tothe adjustment axis 20 and the remaining advance of the wire by the wireguiding means can be prevented by means of a clamping means. A means tothread the wire into the wire guiding means assisted by air jet streamscan be provided in addition to the clamping means.

The connecting means 17 is then driven out as illustrated in FIG. 3B,until it rests on an attachment surface 29 with interposition of thewire 26. In this position, the wire 26 is now connected to theattachment surface 29.

As discussed above, a laser welding means can be included with theconnecting means 17. The laser welding means comprises a laser source 7for providing laser power, which is conveyed to the connecting point viaa glassfibre conductor 5. A protective gas supply means 6 can also beincluded in the region of the connecting means 17 for increasing thecompatibility of the connection between the wire 26 and attachmentsurface as described above.

As illustrated in FIG. 3C, the wire severing means 18 is then alsodriven out so the wire 26 can be severed by the severing means 18 closeto the connecting point. The severed wire end is then aspirated by thesuction means 19.

FIG. 2 shows an example of a possible application of thewinding/connecting device 10 according to the invention in theproduction of a clock coil 31 which is used in electrically operatedclocks and has a winding carrier 32 with a coil winding 33 arrangedthereon. The attachment surfaces of the clock coil 31 are formed by aso-called "captone film" 34 which consists of a plastic film with metalplating 35, 36 arranged thereon. FIG. 2 shows two connecting points 37,38 An the metal plating 35, 36, to which winding wire ends 39, 40 areconnected to the metal plating 35, 36.

The clock coil 31 shown in FIG. 2 can be produced using thewinding/connecting device 10 according to the invention in that a firstconnection between the winding wire 26 and the first metal plating 35 isinitially produced to form the connecting point 37 as shown in FIGS. 3A,3B, 3C. The coil winding 33 is then produced by superimposing arotational movement of the winding carrier 32 round its longitudinalaxis and a translational movement of the tool head 12 in the directionof the arrow 41 and back. As already described hereinbefore, the secondwire connection is finally made at the connecting point 38 and the wire26 severed.

FIGS. 4 and 5 show variations of tool heads in schematic illustrations.

FIG. 4 shows a tool head 56 with a wire guiding means 42 which ispivotal round a pivot 43 transversely to the adjustment axis 20 of thetool head. FIG. 4 shows the wire guiding means 42 in its windingposition orientated substantially parallel to the adjustment axis 20 andin the pivoted state. Owing to the pivotability of the wire guidingmeans 42, it is possible to dispense with a separate deflecting means.Rather, in the embodiment shown in FIG. 4, the winding wire 26 isconveyed through a wire advance with pivoted wire guiding means 42 ontoan attachment surface 44 and is deflected thereon.

In this position, a connecting means 45 which is adjustable in thedirection of the adjustment axis can be driven toward the attachmentsurface 44, the wire 26 coming to rest between the attachment surface 44and a contact surface 46 of the connecting means 45.

In the embodiment shown in FIG. 4, the connecting means 45 is designedin such a way that a further wire guiding means 47, for example in theform of a duct, is formed in it in order to guide an additional wire 48onto the attachment surface 44 so the wire 26 can be connected to theattachment surface 44 simultaneously with the connection of theadditional wire 48 to the attachment surface 44. This additional wire 48can be made up so as to allow the connection of materials of wire 26 andattachment surface 44 which are poorly connectable to one another or areincompatible. It is also possible to adapt the material of theadditional wire 48 to the materials to be connected so as to providespecial corrosion protection or insulation relative to the exterior. Thewire severing means has not been shown in FIG. 4.

FIG. 5 shows a further variation of a schematically illustrated toolhead 49 which, similarly to the tool head 12 shown in FIG. 1, has a wireguiding means 50, a connecting means 51 and a wire severing means 52. Incontrast to the embodiment shown in FIG. 1, the tool head 49 has adeflecting means 53 consisting of a gripping means which is pivotalround a pivot point 54 belonging to the tool head 49. In order to bringthe wire 26 which has been moved downwardly from the wire guiding means50 into a connecting position in which the wire comes to rest betweenthe connecting means 51 and an attachment surface not shown in detail inFIG. 5, the wire 26 is taken up by a gripper 55 of the deflecting means53 and the held wire 26 is pivoted with the gripper round the pivotpoint 54 into its left-hand position shown in FIG. 5. Starting from thiswire position the wire 26 can be connected to an attachment surface andthe wire 26 can then be severed as described hereinbefore in conjunctionwith FIGS. 3B and 3C.

I claim:
 1. A device for producing a coil winding from coil wire on a winding carrier, the device comprising:a winding head movable relative to the winding carrier; wire guiding and supply means for guiding the wire through the winding head to an attachment surface of a substrate, wherein the device is movable along an adjustment axis substantially perpendicular to the attachment surface and the wire guiding and supply means guides the wire through the winding head substantially parallel to the adjustment axis; wire connecting means for producing an electrically conductive connection between the wire and the attachment surface; wire severing means for severing the winding wire after the wire has been connected to the attachment surface; and deflecting means comprising a duct extending through the winding head for deflecting the wire in a direction transverse to the adjustment axis so that the wire is positioned inside the winding head between the connecting means and the attachment surface; wherein the wire guiding and supply means, the wire connecting means, the defecting means and the wire severing means are all provided as integral components of the winding head.
 2. A device according to claim 1 further comprising:at least one adjusting member for actuating or adjusting the wire connecting means, the wire guiding and supply means and the wire severing means along the adjustment axis; wherein the winding head further comprises a tool head; and wherein the wire guiding and supply means, the wire connecting means and the wire severing means are combined in the tool head, and the at least one adjusting member is arranged outside the tool head.
 3. A device according to claim 2 wherein the at least one adjusting member is arranged in a tool head carrier which can be coupled to the tool head.
 4. A device according to claim 2 wherein the at least one adjusting member is a compressed air actuating member.
 5. A device according to claim 2 wherein the at least one adjusting member is a solenoid-type actuating member.
 6. A device according to claims 1 further comprising a laser source, and wherein the wire connecting means is a glassfibre conductor which is integrated into the winding head and is connected to the laser source, the laser source being arranged independently of the winding head.
 7. A device according to claim 1 wherein said attachment surface is an unbumped surface of an electronic component.
 8. A device according to claim 1 wherein said coil wire comprises copper bonding wire.
 9. A device according to claim 1 wherein the wire deflecting means is formed from an aspirator acting transverse to the adjustment axis.
 10. A device according to claim 1 wherein the wire guiding and supply means is pivotal transversely to the adjustment axis.
 11. A device according to claim 1 wherein the wire guiding and supply means is integrated into the wire connecting means.
 12. A device according to claim 1 further comprising a protective gas supply means for supplying protective gas to the wire connecting means.
 13. A device according to claim 12 wherein said electrically conductive connection is made in a protective gas atmosphere provided by the protective gas supply means.
 14. A device according to claim 1 further comprising a vacuum system in a region near the wire connecting means for producing a vacuum in the region near the wire connecting means.
 15. A device according to claim 14 wherein said electrically conductive connection is made in said vacuum.
 16. A device according to claim 1 further comprising a CCD monitoring camera on the tool head.
 17. A device according to claim 1 further comprising a CCD monitoring camera on the winding carrier. 